params : You can specify values for parameters to be passed to Flash
to control the appearance of the output. Typical values are
bgcolor and wmode. Example: params="wmode=true&&bgcolor="#00FF00"
Alternatively you can supply each parameter individually without using
params. Example wmode="true" bgcolor="#00FF00"

flashvars : You can specify values for output as flashvars, which
become available to the Flash movie that is playing. This is often done
to control a media player. Refer to the documentation of the flash player
you are using to know what flashvar options are available.
Example: flashvars="autostart=true&&volume=80"

methods : Optional information about how to display the file. The most
common usage is to specify a particular media player and
thus override the default specified on the settings page.
Example: methods="player=onepixelout_mp3"